With the development of the communication technology, particularly, the rapid development of the wideband communication technology, various modulation modes with high spectrum efficiencies are widely used, wherein the problem of high Peak-to-Average Power Ratios (PAPR) also makes a higher requirement to the linearization technology of the power amplifier (HPA).
Among the linearization technology of the power amplifier, the Digital Pre-Distortion (DPD) technology is a widely used and effective method. The basic principle is to perform pre-distortion processing on a transmitted signal through a pre-distorter having characteristics opposite to the nonlinear characteristics of the power amplifier, before amplifying the signal through the power amplifier, so as to modify the nonlinear characteristics of the whole pre-distortion device (e.g., the transmitter system), thus the whole system presents the linear characteristics so far as possible.
On the other hand, in order to improve the efficiency of the power amplifier, the power supply modulation technology is provided, which is a simple and effective scheme, and the principle is to dynamically adjust the drain bias voltage of the power amplifier according to the output power of the power amplifier, and reduce the DC power consumption of the small-power output, so that the efficiency of the whole system is improved.
To be noted, the above introduction to the technical background is just made for the convenience of clearly and completely describing the technical solutions of the present disclosure, and to facilitate the understanding by a person skilled in the art. It shall not be deemed that the above technical solutions are known to a person skilled in the art just because they have been illustrated in the Background section of the present disclosure.